1. Field of the Invention
This invention relates to a vibrating push button station to be associated with a traffic signal of the kind that is found at an intersection to control vehicular traffic so that pedestrians may cross the intersection once the traffic has been halted. The vibrating push button station of this invention has particular application for generating a tactile feedback signal by which to inform visually impaired pedestrians when the intersection may be crossed.
2. Background Art
It is common to combine a visual display with a traffic signal that is located at an intersection to control vehicular traffic and thereby enable pedestrians to cross the intersection. That is to say, the usual visual display conveys both a written message (i.e., WALK or DON'T WALK) as well as a color sensitive message (i.e., red or white) to instruct pedestrians when to cross the intersection. However, such visual warnings are of little value to those pedestrians who are visually impaired. Consequently, a visually impaired pedestrian who activates the push button of a traffic signal will have no way to accurately know when the intersection has been cleared of traffic so that it is time to cross.
To overcome this pervasive problem, a push button station was invented that is capable of generating a tactile feedback signal (i.e., a vibration) to alert visually impaired pedestrians to cross a traffic signal controlled intersection at the same time that the WALK message is being displayed. This push button station is disclosed in detail in U.S. Pat. No. 6,340,936 issued Jan. 22, 2002 and assigned to the assignee of this application.
In general terms, U.S. Pat. No. 6,340,936 describes a novel push button station having an electromagnetic assembly that generates a signal by which to vibrate a push button after the push button has first been depressed by a visually impaired pedestrian. A piezoelectric member is responsive to the pressure that is applied by the pedestrian to depress the push button. The piezoelectric member generates an output voltage to be received by an external control circuit which ultimately causes the traffic signal to change and the push button to vibrate. The patented push button station includes a solenoid to transfer the pushing force applied by the pedestrian from the push button to the piezoelectric element. More particularly, a magnetic flux that is generated after the push button is depressed causes an armature of the solenoid to move back and forth and repeatedly strike the button.
It is now desirable to eliminate the solenoid which is a part of the patented push button station that has been described above so that the push button station can have a more simplified, efficient and reliable electromagnetic vibrating assembly.